First, fill in the numbers according to the law.

1)64,48,40,36,34,( ) 2)8, 15, 10, 13, 12, 1 1,( )

3) 1, 4, 5, 8, 9, (), 13, (), () 4, 2, 4, 5, 10, 1 1, (), () 5) 5

1. In arithmetic progression, 9 12, 2 1, 30, 39, 48, …

2. Find the sum of all integers between 1 and 100 that are not divisible by 5 or 9.

3. Divide 2 10 by the sum of seven natural numbers, so that after the seven numbers are arranged in a row from small to large, the difference between two adjacent numbers is 5. So, what is the number of 1 and the sixth number?

4. Group all odd numbers starting from 1, where the first number of each group is equal to the number of all numbers in the group, such as (1), (3,5,7), (9,0/1,13,660.

Third, the average problem.

1. The average number of 9 known is 72. After removing a number, the average of the remaining numbers is 78, and the removed number is _ _ _ _ _ _ .2. There are 40 students in a class, and two students are absent for some reason in the midterm math exam. At this time, the average score of the class is 89 points, and the students who are absent from the exam each get 99 points. The average score of the senior high school entrance examination in this class is _ _.

In the first five months of this year, Xiaoming saved money in 4.2 yuan on average every month. Since June, he has saved 6 yuan every month. Since which month, Xiaoming has saved more money than 5 yuan on average?

4. four numbers a, b, c and d, one number at a time, and the remaining three numbers are averaged. This is done four times, and the following four numbers are obtained: 23, 26, 30, 33.

What is the average of a, b, c and D 4?

5 A, B, C, D4, remove one number at a time and take the average of the remaining three numbers. This calculation is done four times to get the following four numbers 23, 26, 30, 33, and the sum of numbers A, B, C and D4 is.

Fourth, simple operations of addition, subtraction, multiplication and division

1) 100-98+96-94+92-90+……+8-6+4-2=( ) 2) 1976+ 1977+……2000- 1975- 1976-……- 1999=( ) 3)26×99 =( )

4)67× 12+67×35+67×52+67=( )

5)( 14+28+39)×(28+39+ 15)-( 14+28+39+ 15)×(28+39)

Five, the number of arrays.

1, △, □, and zero respectively represent three different numbers, and;

△+△+△=〇+〇; 〇+〇+〇+〇=□+□+□; △+σ+σ+□= 60 Find :△ = σ =□ =

2. Fill nine consecutive natural numbers in nine spaces in three rows and three columns, so that the sum of the three numbers in each row and each vertical column is equal to 60.

3. Fill nine consecutive odd numbers starting from 1 into nine spaces in three rows and three columns, so that the sum of three numbers in each row, each column and two diagonal lines is equal.

4 Make up a third-order magic square with 9 numbers from 1 to 9, and write all possible results. The so-called magic square refers to filling different numbers in each square of the square grid table, so that the sum of numbers on each row, column and two diagonal lines is equal; Order refers to the number of squares in each row and column.

Sixth, the problem of sum and difference times.

1. There are 340 peach trees and apricot trees planted in the orchard, of which the number of peach trees is 20 times more than that of apricot trees. How many trees have been planted?

2. Find the area of a rectangle with a circumference of 30cm and a length twice as wide.

3.A and B are two numbers. If A plus 320 equals B, if B plus 460 equals 3 times A, what are these two numbers?

There are two pieces of cloth with the same length. The first piece sells for 25 meters, the second piece sells for 14 meters, and the remaining piece of cloth is twice as long as the first piece. How many meters is each piece of cloth?

There are 150 peach and pear trees in the orchard. There are 20 more peach trees than pear trees. How many fruit trees are there?

6. Two barrels of oil A and B weigh 30 kilograms. If 6 kilograms of oil in barrel A is poured into barrel B, the weight of the two barrels of oil is the same. How much oil do they have?

Seven, the age problem

1. The two brothers are 30 years old this year. When my brother and brother are the same age now, my brother is exactly half his age. How old is my brother this year?

The mother and daughter are 64 years old, and the daughter is three years older than her mother. How old are the mother and daughter?

My brother is older than Xiaoli this year 12 years old. Eight years ago, my brother was four times older than Xiaoli. How old are they this year?

Grandpa is 72 years old and grandson 12 years old. A few years later, grandpa was five times as old as his grandson. A few years ago, my grandfather was 13 times older than my grandson.

Eight. Hypothetical problem

1.42 students participated in tree planting, with an average of 3 trees planted by boys and 2 trees planted by girls, with 56 more trees planted by boys than girls. How many boys and girls are there?

2. A primary school held a math contest with *** 15 questions. He gets 8 points for every right question and 4 points for every wrong question. Xiaoming got 72 points in the exam. How many questions did he get right?

There are 25 questions in a test paper. Answer one question correctly and get 4 points. Answer correctly or not, get 1 point. A classmate will get 60 points. He answered several questions correctly.

4. Xiaohua answers math judgment questions, giving 4 points for a correct answer and 4 points for a wrong answer. She answered 20 true and false questions and got only 56 points. She answered several questions wrong.

5. Yucai Primary School held a math contest in the fifth grade, *** 10. Every time you do a right question, you will get 8 points, and if you do a wrong question, you will be deducted.

5 points, Zhang Xiaoling finally got 4 1 point. How many questions did she answer correctly?

Do it yourself You can't do it well if you have an answer. I'm sorry